No, that's not the "new rules", that's the "rules that have been in place forever, but if you are familiar with Chrome, these are the same." The new rules is that Developer Edition takes place of Aurora in that scheme.

Your "in place forever" conflicts with the comment to which I have asked for an explanation what the new rules are:

callahad:

"5. We have a new channel, which new rules." (sic)

Note that the Developer Edition is definitely new (1), and callahad also explains in his reply where it is positioned:

"As far as fundamental web platform features are concerned, the Developer Edition is a normal pre-Beta channel. It's primarily that more willing to promote new tooling up from Nightly into the DevEdition or to set different default preferences, for instance."

1) https://hacks.mozilla.org/2014/11/mozilla-introduces-the-fir...

We've done that frequently with the Aurora channel too, so in terms of release management rules, it's just a new name and focus for an existing channel.

Does it mean

Developer Edition == Aurora + different default settings + additional tools?

Or, what are the exact differences between Aurora and Developer Edition?

Yeah, pretty much. "Developer Edition" is the new name for the Aurora channel. There is no more "Aurora."

(Well, almost. The "Developer Edition" stuff is desktop-only for now, so the alpha-branch builds for Android are still branded as "Aurora." But Aurora for Andoid and Dev. Edition for desktop are built from the exact same source code.)

These aren't new rules; this has been the Firefox release process since Firefox 5 was released (3.5 years ago).

Good software projects aren't afraid to borrow features and practices that are working elsewhere.